ARM: PSCI: Switch to per-CPU target PC storage in secure data section

Now that we have a secure data section and space to store per-CPU target
PC address, switch to it instead of storing the target PC on the stack.

Also save clobbered r4-r7 registers on the stack and restore them on
return in psci_cpu_on for Tegra, i.MX7, and LS102xA platforms.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
diff --git a/arch/arm/cpu/armv7/psci.S b/arch/arm/cpu/armv7/psci.S
index bfc4475..50dfddb 100644
--- a/arch/arm/cpu/armv7/psci.S
+++ b/arch/arm/cpu/armv7/psci.S
@@ -245,8 +245,7 @@
 	bl	_nonsec_init
 
 	bl	psci_get_cpu_id			@ CPU ID => r0
-	bl	psci_get_cpu_stack_top		@ stack top => r0
-	ldr	r0, [r0]			@ target PC at stack top
+	bl	psci_get_target_pc		@ target PC => r0
 	b	_do_nonsec_entry
 ENDPROC(psci_cpu_entry)